Onirix Constructor: best practices

In this document we will show you how to scan the environment for 3D reconstruction with Onirix Constructor. Onirix Constructor is the native app that allows you to create 3D reconstructions of your immediate environment. Before getting started make sure you have downloaded our app, and have created your Onirix account. You will need to Log in the app with the same account you have created for Onirix Studio.

3D reconstructions with Onirix can be easily created using simple 2D images that anyone can take with their phone! These reconstructions are based on photogrammetry techniques which make it very important to get a good batch of images of the object or the space that you want to reconstruct to achieve a result with the desired quality. But don’t be afraid, it is easier than it seems, since Onirix Constructor already takes care of some aspects for you. Onirix Constructor facilitates the acquisition process, since you only have to tap the capture button once, and the app will decide when to take photos based on your motion, ensuring that you acquire the images with consistent camera settings and the minimum overlap between images.

Image acquisition: best practices

Here’s how to ensure you capture the perfect set of images for your 3D model:

Preparation is Key:

• Plan Your Route: Before you start, think about your movement around the object or space. Clear any obstacles and visualize a path that allows comprehensive coverage.
• Steady Movements: Hold your phone in portrait mode, and proceed with a smooth, even pace. Sharp turns or jolts can interfere with image clarity and tracking precision.
• Keep Walking: To adequately capture your subject, walk around it—this provides a variety of angles for a full reconstruction. Avoid rotating your phone on the spot, as this can disrupt the process.
• Direct Focus: Aim your camera straight at the subject for the best perspective. Extreme angles from above or below can distort the final model.

Optimal Scanning Environment:

• Balanced Lighting: Good lighting is crucial. Aim for soft, even lighting to minimize shadows. This lighting should be maintained in the localization phase.
• Mirror, Mirror, Not on the Wall: Avoid reflective surfaces to prevent confusion during the reconstruction.
• Still Life: Movement can be the enemy of a good scan. Make sure both your subject and its surroundings remain undisturbed.
• Rich in Texture: Textured surfaces provide crucial information for 3D reconstruction. Avoid scanning areas without distinguishable features.

Guidelines about camera motions

Good camera motions

These camera motions capture a scene or object in a manner that adds to the overall results of the 3D reconstruction. A majority of camera movement during a capture session should consist of good motions. Displacement: moving across the scene in a straight trajectory while the camera is pointed perpendicular to your motion or maintaining the view point

Arc: Moving around and object in a curving trajectory while keeping the camera pointed at fixed point

Bad camera motions

These camera motions capture a scene or an object in a manner that negatively impacts the results of the 3D reconstruction.

Pure rotations (pan and tilt): these motions are characterized by swiveling the camera horizontally or vertically from a fixed position (without displacement).

Transition camera motions The following camera motions capture a scene or object in a manner that does not add to the overall results of the 3D reconstruction. These motions are used to connect two good motions in order to gain new perspectives and angles on a scene

Get closer or further: this motion is characterized by moving closer or further to a scene or object with the camera pointed parallel to the direction of movement.

Roll: this motion is characterized by the camera rotating over its side on its long axis.

Guidelines for object scanning

Do not start very close to your target object and walk a full circle around it, while keeping the target in view. Do not just rotate around a single spot or wave the phone without actually moving. This will allow you to take photos from all angles around the object.

Guidelines for space scanning

• Plan Your Path: Before starting, plan a path that covers the entire room efficiently, ensuring all areas are captured.
• Direct Focus: Aim your camera straight at elements of interest. So, if you are walking through an aisle and you want to scan the furniture that is along the wall you must focus that furniture with the camera instead of focusing on the aisle direction.

• Avoid the pure rotations especially when you are scanning a corner. It is preferable to use arc motion.

• Feature Rich Areas: Focus on areas with lots of details, as they help in aligning images during reconstruction.
• Overlap Between Walls: Ensure that there is overlap where the walls meet the floor and ceiling.